The discovery of catalyst material compositions from among almost limitless material or compositional possibilities, layer configurations, and material proportions has typically required the one by one fabrication of a sample on a specified substrate, followed by the proper testing—typically a very time consuming process. In the prior art, when physical vapor deposition (PVD) processes are used in the synthesis of catalytic samples, one by one, for testing, expensive and complex equipment and repetitive test protocols are involved that consume considerable time. In the system of the present invention, a high throughput system for synthesizing a group of catalyst compositions at the same time (namely in a same batch) for subsequent testing is provided.
In the case of coating a material using a PVD system, it is often required that the targets of the plasma guns be exchanged frequently—a time consuming procedure when hundreds, or thousands, of discrete, individual material combinations are to be tested for suitability. The invention of the system described herein allows multiple different samples to be created in batches and expedites the preparation and testing of sample materials that are theoretically or empirically identified as candidates for practical use in specified potential applications. For example, in combination with a multi-channel rotating disk electrode assembly, suitable electrocatalysts for a predetermined application may be synthesized, evaluated and consequently discovered.
As referred to herein, high throughput catalyst discovery refers to the methodology of creating at the same time a large number of chemical compositions that are subsequently tested and/or evaluated for use in a specified process environment in which a catalyst is intended to be operative. In the conventional catalyst discovery process, each individual compound is separately created and tested. In the high throughput/combinatorial studies to which the present application is directed, the deposit of different varieties of functional materials or chemical compositions, on different defined areas of a single substrate, or on an assembled combination of a large number of separate substrate samples, allows the different deposited materials to be synthesized, essentially simultaneously, together. Thus, using the system of the invention, it is possible to produce hundreds, or even thousands, of potential catalyst composition samples during a working day.
Typically, the discovery of a catalyst that is suitable for a particular application (determined by factors of efficiency, economy, size, and ease of synthesis, among others) is frequently a trial and error procedure, which in the instance of PVD procedures, is further complicated because the catalyst may be a co-deposition or multi-layered composition formed from multiple constituents. Numerous combinations of materials, proportions, mixtures layers and other factors are possible. Constituent materials are selected; their order in layers is determined; their co-deposition component percentages, if applicable, are estimated; and the resulting catalyst is then synthesized and subsequently evaluated for suitability for a specific application.
There exists a need for a high throughput system for efficiently synthesizing multiple variations of different catalyst compositions for testing. Thus, it is an object of this invention to provide an infinitely variable, programmable PVD plasma gun cluster and matrix system to allow the essentially simultaneous fabrication of multiple, different combinatorial catalyst samples in a batch, by the co-deposition of multiple materials or the sequential layer by layer deposition of multiple catalyst constituents, for testing. The optimum mix of materials, within the range of the multiple batch samples produced, for a pre-specified application, can be determined in subsequent testing.
The invention is described more fully in the following description of the preferred embodiment considered in view of the drawings in which: